A FULLY NONLINEAR FINITE ELEMENT MODEL FOR ORTHODONTIC TOOTH MOVEMENT PREDICTION.

This work presents a finite element model of a tooth and its surrounding tissues in orthodontic tooth movements. It includes the following features: the periodontal ligament mechanical behaviour is modelled as nonlinear bilateral contact conditions between the bone and the tooth; the alveolar bone is considered as an anisotropic organisation of elastoplastic trabeculae; a remodelling algorithm accounting for the pressure dependency due to the periodontal ligament cellular activity is used. We test this model for two types of loading. The first, applying a pressure to the crown, leads to a remodelling along the whole height of the tooth, leading to a tipping movement. The displacement of the tooth for a constant force increases in time due to remodelling. The second, applying a constant rotation of the tooth, shows a decrease of the force needed to keep the rotation angle as well as a latency period before a decrease of the force. Using a pressure dependency of the remodelling rate therefore allows representing most features of orthodontic tooth movement in both the loading cases presented